They'd only change it to warrior from woman if it's sexist to single out that she is ONLY the most dangerous compared to all other women, or some other unintended slight where it's floated by idiots looking for a fight that it's rude to suggest that women can't compete with men. And besides, how do you define "warrior" in a futuristic alien society? It's an impossibly ill-defined group of DANGEROUS people who when you really think about it would never really describe themselves as warriors. Warrior is an old timey word which they only used as a substitute because it's phonetically similar.

Who would be offended by a master assassin and Death's stepdaughter... DEATH'S STEPDAUGHTER being referred to as the most dangerous Woman in the Universe?

Surely the most dangerous woman in the universe would be at least as dangerous as almost %100 of the men in the universe (Gamora vs Thor? Thor goes down.)?

And the real truth is that Gamora is most certainly not the most dangerous woman in the Universe, probably not even close, it's just her blurb, but in an effort to remove any hint of a glass ceiling, they increased the scope of that lie by balling together both genders and claiming that she's the most deadly Warrior in the universe.